a) Field of the Invention
The invention is directed to an endoscoping arrangement comprising an endoscope with a needle-shaped tube which has a lens system on its distal end provided for insertion into the body, and with a viewing field diaphragm provided at a proximal viewing-side end of the endoscope, and a coupling device for connection of the endoscope to a video camera, the coupling device being attachable to the proximal end of the endoscope.
b) Description of the Related Art
A known endoscope of the type mentioned above is described as a videoarthroscope in U.S. Pat. No. 4,969,450. In this known endoscope, the proximal end of the needle-shaped tube on the one hand and the distal end of the coupling device on the other hand are attached to a middle part which has a connection for a light source, the light coming from the light source being guided by a glass fiber bundle contained in the connection via the middle part through the tube-shaped needle to the distal end of the latter.
The coupling device has a first lens system facing a field diaphragm provided on the proximal end of the needle-shaped tube and another, second lens system on its proximal end, facing the video camera, wherein the first lens system is fastened in a sleeve which is mounted in a coupling device so as to be longitudinally displaceable, so that the image transmitted by the endoscope and the lens transmission and image transmission system contained in the needle-shaped tube, respectively, can be focused and correspondingly transmitted to the CCD chip contained in the video camera. For this purpose, the coupling device has on its outside a sleeve-shaped actuating member that can be rotated around its longitudinal axis and with which the first lens system can be moved in an axial direction.
Endoscopes outfitted with video cameras and having an eyepiece fixedly attached to their proximal end are also known. In endoscopes of this type, the coupling device which can be focused and which is necessary for the connection of the video camera is attached at or to the eyepiece, for example, by means of suitably constructed clamping devices. Apart from the fact that such endoscopes and coupling devices can principally not be autoclaved, the form of fastening the coupling device to the eyepiece also represents a very unstable fastening device.
It is absolutely indispensable for endoscopes to be sterilized perfectly, i.e., so as to be completely free of germs, after use or before being put to use again. However, freedom from germs is only guaranteed if the instrument can be autoclaved, that is, exposed to very high temperatures and pressures. In the case of the known endoscope with its coupling device for connection of the video camera, autoclaving is not possible because, in view of the above-described adjustability of the lens system contained in the coupling device, it cannot be constructed in a sufficiently tight and hermetically sealed manner to prevent hot steam from entering into the coupling device and accordingly rendering opaque the lenses contained therein. For this reason, these endoscopes and coupling devices are merely put into sterilizing solutions and are consequently not as well sterilized as they would be when autoclaved.
Therefore, it is the primary object of the invention to provide an endoscope with a coupling device for connection of a video camera, both of which can be autoclaved completely, possibly together, as the case may be, that is, without the need for disassembly.
This object is met for an endoscope arrangement of the type mentioned in the introduction in that the endoscope has, at its proximal end, a lens system which follows the field diaphragm and which, like the lens system at the distal end, is completely and tightly sealed off from the outside and is not adjustable/cannot be focused, and in that the coupling device does not have a lens and is adjustable along its axial length in the manner of a telescope.
Due to the fact that a lens system which cannot be adjusted/focused is provided at the proximal end of the endoscope following the field diaphragm, the endoscope, including its middle part and its light connection and the two ends of the tube, can be hermetically sealed toward the outside and can therefore be autoclavable in its entirety. Furthermore, since a lens system is arranged in the proximal end of the endoscope, it is no longer necessary to arrange a lens system in the coupling device; it is sufficient for the latter to be designed in such a way that it can change the distance between the CCD chip arranged in the video camera, which records the image of the operating field supplied by the endoscope, and the lens system arranged in the proximal end of the endoscope. Accordingly, the coupling device can be constructed as a simple telescope-like, hollow-cylindrical body which can be fully autoclaved like the hermetically sealed endoscope.
In a further advantageous development of the invention, the coupling device has a sleeve-shaped shaft of a certain length whose distal end is designed to be fastened to the endoscope, and a focusing sleeve is inserted in the shaft so as to be longitudinally displaceable, a fastening device for connection of the video camera or an eyepiece being provided at the proximal end of the focusing sleeve.
This construction of the coupling device ensures that the video camera which is connected to the proximal end of the focusing sleeve by means of the fastening device can be adjusted, along with its CCD chip, with respect to distance relative to the proximal end of the endoscope, that is, can be adjusted so as to be more or less far away. In this way, the image of the operating field delivered by the endoscope is focused mechanically on the CCD chip of the video camera or on the retina of the eye of the observer looking into the eyepiece which is mounted in place of the video camera at the proximal end of the focusing sleeve.
According to the invention, the shaft is surrounded by an adjusting sleeve, there being formed in the inside wall of the adjusting sleeve a groove which is shaped like or which follows a course like a thread and has a relatively large pitch, and the focusing sleeve has a radial pin projecting outward on its distal end, for example, in the shape of a pin-shaped screw, which projects into the groove of the adjusting sleeve through an axially extending slit provided in the shaft.
This special construction of the coupling device ensures that the focusing sleeve does not twist inside the shaft and only moves in an axial direction when the adjusting sleeve is actuated.
The adjusting sleeve is advantageously mounted on the shaft so as to be rotatable and so as to prevent an axial displacement thereon between two stops which are formed at the shaft and arranged at a distance from one another.
This special construction of the adjusting sleeve ensures that the focusing sleeve can be displaced inside the shaft simply by rotating it.
In a further advantageous development the pin is constructed as a pin-shaped screw that is screwed into a bore hole provided in the focusing sleeve. This construction of the pin effecting the longitudinal displacement of the focusing sleeve permits a relatively simple construction of the focusing sleeve in which only a radial bore hole must be provided; the pin-shaped screw can then be screwed into this radial bore hole.
The screw has a circumferentially extending projection which projects radially outward and which is formed on the outer wall of the focusing sleeve as a stop for limiting the screw-in depth.
Accordingly, the screw-in depth or the distance by which the pin-shaped screw projects radially beyond the outer radius of the focusing sleeve are determined in a simple manner.
Finally, the fastening device for connection of the video camera or an eyepiece is advantageously realized as an adjusting ring rotatably mounted on the proximal end of the focusing sleeve.
The fastening device can be turned by means of this adjusting ring and the video camera or the eyepiece can thus be turned in its position relative to the endoscope, depending on how the image of the operating field received by the endoscope is to be represented.
Also, an eyepiece can be provided on the proximal end of the coupling device instead of the video camera, so that the user of the endoscope has the option of looking into the endoscope himself, that is, without using a video camera or a video setup.
In an advantageous further development of the endoscoping arrangement, the beam path of the endoscope between the lens system in the distal end and the lens system in the proximal end is deflected by means of an intermediately arranged prism, and the deflection is provided adjacent to the field diaphragm.
The arrangement of a deflection of this kind by means of a prism in the above-described area, that is, in front of the lens system in the proximal end of the endoscope and, in particular, in front of the coupling device without any lenses, makes possible an endoscope design in which the connection part for the video camera is outside of the immediate radial working area of the tube of the endoscope.
It is advantageous for the prism to be a 90-degree or right-angle prism; this results in a maximal deflection of the connection part for the video camera out of the working area of the endoscope.
In a further advantageous development, the endoscope has, in the area of deflection, a connection piece for mounting an operating shaft which is not described more fully in this application. Through the operating shaft, the operator can operate in connection with the endoscope, in particular the tube of the endoscope, and at the same time observe the operating field more accurately without being obstructed by the connected video camera.
The operating shaft advantageously has a receiving piece adapted to the connection piece of the endoscope. With this receiving piece, the operating shaft can be connected to the endoscope in a simple manner and in a precisely fixed position.
In a further advantageous development, the receiving piece contains a locking mechanism that enters into a positive engagement with the connection piece when the receiving piece is slid onto the connection piece. This special construction of the receiving piece in connection with the connection piece results in a stable and secure connection between the endoscope and the operating shaft.
Embodiment examples of the endoscope with a coupling device for connection of a video camera that do not limit the invention are described in the following with reference to the figures represented in the drawings.